I support HTML, JS, Python and CSS. For HTML, (not technically an AST), I give the LLM the original-file HTML source, and then I instruct it to write python code that uses BeautifulSoup to modify the HTML. Then I get the string back from python of the full HTML file, modified according to the user prompt.
For python changes I use ast and astor packages, for JS I use esprima/escodegen/estraverse, and for CSS I use postcss. The process is the same for each one: I give the original input souce file, and I instruct the LLM to parse the file into AST form and then write code that modifies that AST.
I took a look at your project and while it's nice (technically), for the actual use case shown, I can't see the value over something like the old Dreamweaver with a bit of training.
I still think like prompting is still the wrong interface for programming systems. Even though they're restricted, configurations forms, visual programming with nodes, and small scripts attached to objects on a platform is way more reliable and useful.
Appreciate you having a look and for that feedback, thanks - I do agree I have work to do to prove that my idea is better than alternatives. We'll see...